Could Chemical Signals Replace Radio in Extreme Environments?

Low-speed chemical messages could prove more effective than traditional technologies in many emergency response scenarios.

The first message transmitted using an airborne alcohol spray was decoded as “O CANADA” using the researchers’ binary coding scheme, the International Telegraph Alphabet No. 2.PLOS One Journal

In the U.K., researchers are studying how to communicate like animals do -- by sending messages with chemicals (along the lines of pheromones).

Developed by Weisi Guo of the University of Warwick in the U.K, and Professor Andrew Eckford and Ph.D. student Nariman Farsad of York University in Toronto, the first message transmitted using an airborne alcohol spray was “10101100111000101011110110,” decoded as “O CANADA” using the researchers’ binary coding scheme (the International Telegraph Alphabet No. 2).

With a data rate of one bit every three seconds, chemicals won’t be used for video streaming any time soon, but if adopted, this technology could begin replacing radio in many emergency response scenarios within the next two years.

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The technology works in much the same fashion as smoke signals or Morse code. In the experiments, a chemical, in this case alcohol, was emitted from a sprayer. A spray represents 1 and a pause represents 0. An Arduino-based receiver was built to interpret and decode the spray signal, which was received from distances of two, three and four meters. The "O CANADA" output was displayed on a small screen. Researchers concluded that the method was highly reliable at short distances.

The data rate of such chemical communication is slow, but still fast enough for many practical applications of inter-robot communication, Eckford said – it’s basically like getting an answer to a yes or no question every three seconds, which is comparable to human interaction. For instance: “Is it safe to go this way?” “Yes.”

The applications they’re looking at now, Eckford said, are environments where radio doesn’t work well, such as in sewers where there’s a lot of water and tight spaces, collapsed buildings with debris that radio has trouble passing through, shipwrecks or caves where water and objects prevent the effective use of radio, and burning buildings where smoke and other obstructions prevent traditional forms of communication.

“When you inspect a sewer system today it’s a big deal,” Eckford said. “You have to put down a special robot, it needs a tether because it can’t send radio signals back. You can’t send down autonomous devices. What we’re thinking about is something like having automated robots constantly going through the sewer system, mapping it out, seeing if there’s anything wrong and sending information to each other."

And if there’s any kind of emergency, they could surface at a manhole and then send a video signal, he said.

A robot traveling down a sewer that came to a branch in the tunnel could ask another robot which way it should go. In a matter of seconds, the robot would know which branch needs help exploring and which branch has already been mapped, much as cells or bacteria communicate on a microscopic level -- which is actually how Eckford and his colleagues first began thinking about this research.

Development for the nano scale is the long-term goal of this research, Eckford said, and such developments could completely change how medicine is administered. This was the goal when this research was first conceived, he said. But nanoscale research is expensive and they lacked the necessary funding, so they decided to start at the macro level.

Since starting this research, Eckford and his colleagues realized that their macrolevel research had practical applications, too. In fact, Eckford said, the technology is ready and there’s no reason it couldn’t find its way into new products in the next year or two.

One environment considered in their macrolevel research was inside a jet turbine – finding a way to transmit telemetry data from inside a very hot, ionized environment where electronic transmission would be difficult. This problem is very similar to the environments faced by firefighters, Eckford pointed out.

Other researchers have also recognized the burning building communication problem, going so far as to develop hologram and laser technology to overcome high temperatures, smoke and unanticipated physical barriers. In extreme environments, traditional communication often doesn't function.

In many search and rescue missions, robots are used alongside humans, and the ultimate goal for many scientists is to take humans completely out of danger’s way in such scenarios.

“We’re suggesting maybe you could actually use robots that communicate and cooperate at very low speed using this chemical link, but that should be [fast] enough to help them coordinate their efforts and search safely without having to risk a human,” Eckford said.